ceph-volume: do not print the secret of osd keyring

ceph-volume: do not print the secret of osd keyring

during osd preparation, ceph-volume logs the secret of the osd keyring to file
```
[2022-06-15 12:31:17,466][ceph_volume.process][INFO  ] Running command: /usr/bin/ceph-authtool /var/lib/ceph/osd/ceph-0/keyring --create-keyring --name osd.0 --add-key AQAM0aliR5JvDRAAQBu0stWl9ZhZrcjijg2BIQ==
[2022-06-15 12:31:17,481][ceph_volume.process][INFO  ] stdout creating /var/lib/ceph/osd/ceph-0/keyring
added entity osd.0 auth(key=AQAM0aliR5JvDRAAQBu0stWl9ZhZrcjijg2BIQ==)
```

This shouldn't be logged nor printed on terminal.

Fixes: https://tracker.ceph.com/issues/56071
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>